Book-rack.



J. G. LARSON BOOK RACK.

APPLICATION min DEC. l, 1913.

Patented 0G17. 30, 1917 /J- L um WTVESSES.' @QM W C @MQ themselves to bring the son ien. f

i JOHN G. LARSON, y01E" OAKLAND, CALIFORNIA.

BOOK-RACK.

Specicatlon of Letters Patent.

Patented oet. so, 1917.

Application led December l, 1913. Serial No. 803,939.

To all whom t may concern.' l

VBe it known that I, Jox-IN G. LARsoN, a citizen of the United' States, residing at Oakland, in the county of Alameda and State of California, have invented certain new. and useful VImprovements in Bookacks,V of which the. following is a specication. f

This invention relates to book holders and more particularly to a device for supporting loose leaf ledgers and the like, so that the pages thereof present a flat writing surface, on a level with a stationary arm rest.

The principal objectofmy invention is to provide a support-for the purpose set forth, having two flexibly connected back rests, so supported that they automatically adjustwriting surface level with the arm rest no matter at what page the book is opened.y

Another object is to provide means for changing the length ofthe said lieXible connection so as to take care of various sized books. f fr Y With these and other objectsin view my invention consists in the new and novel Construction and arrangement of parts as hereinafter described and illustrated in the accompanying drawings, and as more specically pointed out in the-*claims `hereunto annexed. f

Referring to the attached drawing forming apart of this specification, v

Figure 1 is a view in plan of my improved device showing the same without a book thereon.

Fig. 2 is a view in section on 2 2 Fig. 1 showing in outline an open book positioned thereon.

Fig. 3 is a view in section on 3-3 Fig. 1.

Fig. 4 is a view in section on 4 4 Fig. 1.

Denoting corresponding parts by the same numerals of reference, 1 is a substantially rectangular frame having the end walls 2 front and rear walls 3 and 4 respectively. Tntermediate 3 and 1 is a division wall 5 attached to the ends 2. Over the space 5 thus formed between division wall 5 and front wall 3 is placed an adjustable cover plate 6, which forms an arm rest.

The adjustment of this arm rest is effected by providing depending guides 7 adjacent each end of the rest, which fit closely within the rectangular cavity 5 and in these guides are provided angularly disposed slots 8. The end plates 2 are also slotted as at 9,

14 of that plate.

which slots are provided with circular serrations V10. The latter are of such size that a pin 11 is held therein against longitudinal movement. VThus to adjust the heightof the vrest it is only necessary to raisethe same to the required height and insertthe pin 11 lthrough the serration in alinement with the incline slot 8.

The rest for the book shownin dotted outlines at 12 consists of two flat'plates 13 and 13 slidable on the inclined guide bars 14.

As shown on the dra-wing I provide slots 15 in the end of plates 13 and 13 in which `the bars 1st lit but if desired the plates may be fitted with rollers which engagefthese bars thus making the movement of` theplates easier. f

The plates are connected by an inelastic flexible strip 17 the end being held fast to plate13 by a strip V16 nailed or screwed thereon while the otherends pass freely between the plate 13 and strip 16 secured thereon` and are secured to a roller 18. This roller is pivotally mounted'in bearings 19 and 19\v and on one worm Wheel 20. A

A worm 21`meshing Vwith the latter is revolubly mounted in `extension of bearing 19f`and `the shaft thereof is provided with a squaredvend, which extends into -a hole in end is securedy a toothed plate 13"'rendering it accessible for adjustment from above. j j j i Inuse the flexible strips 17 are adjusted until ywith the back of the book resting thereon the covers lie flat on the plates 13 and 13. Now when the book is opened near the front, plate 13 is depressed while 13 is correspondingly elevated causing the opposite pages to lie in a substantially horizontal plane. The arm rest can then be adjusted to give the greatest ease in writing on these pages.

As the pages are turned to the left plate 13 will be depressed causing the strip 17 to pull plate 13 to the left. This force. will in turn cause the latter plate to move upwardly and to the left along the guideways Even when plate 13 is below the level of plate 13, this same action will take place until the portion of the strip 17 adjacent the plate 13 is at right angles to the inclination of the guideways, as until this position occurs there is a resultant force which tends to move the plate upwardly. Thus as the plate 13 is depressed 13 is elevated so as to maintain the upper surfaces of the pages of the book at approximately the saine level.

From the foregoing description it will be seen that l have provided a simple and eflective device, which accomplishes the objects hereinbefore set forth, and While l have showed the preferred embodiment of my inyention it Will be understood that minor changes may be made in form and detail Without departing from the spirit thereof.

wWhat l claim as new and Wish to coter by Letters Patent is1- l. A bookrholder comprising a frame, a pair of plates for supporting covers of a book, means for slid-ably supporting said plates, and a `flexible member connectingk said plates to permit either plate to rise as the other is depressed by the Weight ot that portion of a book supported thereby.

Y 2. A book holder comprising frame, a pair of plates for supporting covers 'of a book, means for slidably supporting `said plates to permit either plate to rise as the other is depressed by the Weight of that portion of a book supported thereby, a ilexible member connecting said plates and means for varying the effective length of said flexible connection. 3. A. book holder comprising a frame, up-

wardly converging guideways, plates engaging said guideways forming rests for the respectivey book covers, and a flexible sub stantially inelastic connection bet-Ween said plates, so that when the pages of said book are turned one plate may be. depressed While the other is moved upwardly.

e. A book holder comprising aframe, a pair of plates forming `rests for thev book covers, a plurality of ,parallel inclined guides engaging opposite edges of each of said plates, the guides of opposite plates being upwardly converging, flexible substantially inelastic strips Yconnecting the adjacent edges YVof said plates, so that when either plate is depressed the other plate is constrained to move upwardly along its guides, and means for ifarying the eectiye length of said strip.

5. A book holder comprising a frame, a pair of plates forming rests for the respec.- tive covers of a book, guides on which said plates are slidably mounted, the guides of opposite plates converging toward each other, adjustable flexible substantially inelastic strips connecting the inner edges of said plates so that when either plate is depressed along one guide the other is constrained by said strips to more upwardly alongthe oppositely inclined guide.

G. L book holder comprising aframe, a 60 pair of plates forming rests for the book coyers, pairs of parallel inclined guides engaging opposite edges of each of said plates, the guides of opposite plates being upwardly converging, adjustable flexible substantially inelastic strips connecting the adjacent edges of said plates, so that when either plate is depressed the other plate is -constrained to more upwardly along its guides,

a reel on the underside of one of said plates to which said strips are attacheck and means for turning said reel toy Vary the length of said strips.

in testimony whereof l atlix my signature in presence of two Witnesses.

y JOHN Gr. LABS/ON. 1llVitnesses;` l l B. M. Grenze, W. A. STOCK.

Copies of this patent may beobtane. for fivefeents each, by addressing the Commissioner of atents, Washington, D. 

